What happens in the field stays in the field…until now.

bats

This week Dispatches from the Field is excited to welcome back Toby J. Thorne, who wants to share with you a sneak peak into the “Bats of Ontario” field guide he wrote. Check out the end of the post for where to purchase it!

Most field biologists will consult a field guide at some point in their careers. Whatever critters you’re studying, it helps to know what they look like, along with basic characteristics or measurements! Certainly I have accumulated my own small collection of field guides over the years. Field guides are exciting: filled with aspiration, and the promise of new adventures and discoveries. They are also working books. A true field guide is intended to be well thumbed, stuffed into packs, and referenced in all weathers.

But despite my love of field guides, I never gave much thought to where they come from. At least, not until someone suggested I write one.

For the past few years I have volunteered with the Matt Holder Environmental Education Fund. Founded by Phill and Sue Holder, the fund is in memory of their son Matt, a keen naturalist who died unexpectedly young. The fund’s goal is to provide opportunities for young people to get involved in nature, and Phill hopes to support the fund through the sale of field guides. To this end, he produces a range of well put-together guides. To date these include books on birds and moths in Southern Ontario, along with several checklists for Thickson’s Woods in Whitby, where the fund’s activities are centered. When he suggested I should write one for bats in Ontario I couldn’t say no!

A good guidebook is important when working with bats. In the tropics there can be hundreds of species, many of them understudied. In more temperate regions such as Canada, there are fewer species – for example, Ontario is home to just eight. Yet while there are not many species to learn for Ontario, figuring out how to tell them apart can be quite tricky. To add further confusion, there are two distinct identification methods for bats.

One way is to catch them and have a close up look. This works most of the time (if you have the appropriate skills and permits to do so), but sometimes it’s easier said than done. I have previously caught two species of European bats whose key differences are a tiny tooth cusp and penis shape. The second of those is only useful about half the time!

A hoary bat, Ontario’s largest species, in flight. Although the bat’s open mouth and bared teeth may appear aggressive, this is actually just the bat echolocating to ‘see’ its way. Photo by Brock Fenton.

The second way to identify bats is to monitor them acoustically. Due to the difficulty and invasiveness of catching them, this is often the preferred method. Acoustic monitoring involves listening to the echolocation calls bats make during flight. The calls allow us to determine where bats are, and get a relative measure of bat activity. We can also try to differentiate between species of bat by their differing calls.

In practice, using calls to identify species is not simple. Bat echolocation calls depend on an individual’s environment and what it is doing. This means that different species of bats that are doing similar things can sound similar. Also, to make it more confusing, the same bat can sound quite different depending on what it is doing!

These difficulties keep life interesting when you’re trying to ID bats, and made assembling a field guide seem like an attractive challenge. When I started, there was an excellent earlier guide still available, but at ten years old it is a little out of date on a few things, so producing my own guide was also an excellent opportunity to share some more up-to- date information.

An initial problem (and the one that worried me the most), was assembling suitable illustrations. Most of my own photo collection is of UK species, as that was where I first learned about bats before moving to Canada for my MSc. Since arriving in Canada I’ve managed to photograph some species, but not them all.

Luckily, Phill came up trumps on this front. He was able to negotiate the use of artwork by Fiona Reid, an incredible wildlife artist, for the guide. Fiona is the author and illustrator of the Peterson Guide to Mammals of North America. Phill has set the layout of the book around life size reproductions of Fiona’s illustration of each species, and the use of her artwork has elevated the book to something much better than I could have hoped.

Once Fiona had agreed to contribute her illustrations, I really started to feel the pressure to match her efforts with equal effort of my own! Over the past few years, living in Ontario and working with bats, I have become familiar with the local bat species. However, writing the species descriptions for the guide called for some research. It was necessary to fill in a few gaps and check for knowledge I’d not come across. Also, this was an opportunity to check the things I already ‘knew’. It’s always good to question ourselves!

A little brown myotis bat in flight. Previously widespread, many populations of this species have declined massively in Ontario and eastern North America in recent years. Photo by Brock Fenton.

While species accounts are the key parts of a guide, I found that I also enjoyed writing the introductory sections, which included background information about bats. There are also several sections aimed at beginners interested in learning how to watch bats.

Overall, producing the book has been a great experience, and I learned a lot in the process. It is great to have the chance to share that knowledge and hopefully encourage more interest in these amazing animals! Currently, bats are facing several worrying conservation threats (particularly in North America), and they need all the friends they can get!

Toby caught his first bat at the age of eleven, and has been chasing them every since. After spending his teenage years catching and learning about bats in the UK and completed an undergraduate degree in Biology at the University of Oxford. He moved to Canada in 2013 to undertake a researcher masters supervised by renowned bat researcher Dr. Brock Fenton. Since graduating he has continued to work on bat projects, and currently divides his time between the Ontario Land Trust Alliance and the Toronto Zoo, where he is spearheading the Zoo’s Native Bat Conservation Program.